/etc/protocols seemed so empty (and I realized a few protocols that
are actually used are missing), so I created a patch to add a _lot_
of new data in.
This has been adapted from FreeBSD with the following guideline:
I don't change existing protocol names and numbers unless
they're plain _wrong_ (idpr-cmtp, rspf) so I wouldn't break anything.
If this is useful, I could perhaps do the same for /etc/services.
That would be a bigger job though.